Ni3Si intermetallic compounds, which are nickel intermetallic compounds, have excellent characteristics such as high-temperature strength, corrosion resistance and oxidation resistance. However, polycrystalline Ni3Si intermetallic compounds are brittle as being prone to intergranular fracture, and therefore an intermetallic compound having enhanced ductility and enabled for plastic working at room temperature has been desired. To this end, research and development for improving the Ni3Si intermetallic compounds has been promoted.
For example, an Ni3(Si, Ti)-based intermetallic compound, which is a nickel intermetallic compound, is known as a workable (ductile) intermetallic compound (see Non-Patent Document 1, for example).
In regard to such an Ni3(Si, Ti)-based intermetallic compound, for example, a method for producing a foil of an Ni3(Si, Ti)-based intermetallic compound composed of Ni, Si, Ti and B is known, and it is known that the foil of the Ni3(Si, Ti)-based intermetallic compound produced according to this method has enhanced strength characteristics in a range of temperature from room temperature to 600° C. (see Patent Document 1, for example). The Ni3(Si, Ti)-based intermetallic compound is expected to be applied to catalyst carriers for automobile exhaust control systems and aircraft structural materials, for example.
In addition, an Ni3(Si, Ti)-based intermetallic compound containing specified amounts of Nb and Cr is known as an Ni3(Si, Ti)-based intermetallic compound enabled for plastic working, and it is known that the Ni3(Si, Ti)-based intermetallic compound can be easily worked into a foil (see Patent Document 2, for example).
Furthermore, Ni3(Si, Ti)-based intermetallic compounds containing Ni, Si, Ti and Cu are known as Ni3(Si, Ti)-based intermetallic compounds having ductility, though their workability into a foil is not known (see Patent Documents 3 and 4, for example). Besides, an Ni-based superalloy to which high-concentration Co and Ti are added is known, though it is not an Ni3(Si, Ti)-based intermetallic compound (see Patent Document 5, for example). This alloy has a gamma prime phase including (Ni/Co)3(Al/Ti/Ta).